Photographic silver halide photosensitive material, hereinafter referred to as photosensitive material after exposure is processed through a series of steps including color development, desilvering, washing and stabilization in the case of color photosensitive material. There are used color developer for color development, bleaching, blix and fixing solutions for desilvering, city water for washing, and stabilizer for stabilization. Black-and-white photosensitive material is processed through a series of steps including black-and-white development, fixation, and washing. In either case, photosensitive material is generally processed by dipping them in the respective solutions which are normally adjusted to a temperature of 20.degree. to 50.degree. C.
In the commercial practice of such processing of photo-sensitive material, it is desired to achieve stable and acceptable processing performance with a permissible minimal amount of processing solution for the purposes of reducing the cost, manual work, pollution loads, and processor size as well as improving the commodity value of processed ones.
The stability of processing performance is obtained by maintaining the processing solution composition within a desired range at all times and the superiority of processing performance is obtained by uniform immersion in a sufficient volume of processing solution.
Therefore, as found in color development laboratories, the commercial practice of processing color photosensitive material uses an automatic processor having processing tanks containing large volumes of processing solution. The processor is designed such that whenever a predetermined quantity of color photosensitive material has been processed, a replenisher is automatically fed to the used processing solution to compensate for its exhaustion and maintaining the processing solution within the desired composition range.
In response to the consumers desire to get color prints instantaneously and interest in color processing business with small investments and the like, the color photosensitive material processing is in the phase of shifting from the conventional centralized processing in big laboratories to diversified small quantity processing in many mini-labos and further to small quantity rapid processing.
The processing steps for photosensitive material will now be discussed. Development and bleaching steps of processing imagewise exposed film, typically use processing solutions which experience a varying degree of exhaustion since the amount of silver to be developed with exposure. In the prior art, the operator decided processing conditions by presuming the degree of exhaustion of the processing solution from the known number of film rolls processed or film length. However, since the amount of silver to be developed varies with exposure conditions which in turn, vary with each of exposed picture frames, the degree of exhaustion of the processing solution varies between different film strips. Therefore, for obtaining good and uniform pictures, it is desirable to determine processing conditions for an individual film strip by considering its exposure conditions.
Particularly, in the case of a mini-labo processor intended for small quantity rapid processing, a limited size processing tank is filled with relatively small volume of processing solution which relatively experiences a greater degree of exhaustion per roll of film. It is then desirable to determine processing conditions for an individual roll of film by taking into account the amount of silver developed inherent to the film.
The mini-labo processor has to be kept in the standby state in which the processing solutions are adjusted to optimum temperature so as to quickly meet the consumers' demand while the processing quantity widely varies day by day. Slit type processing tanks which are designed to provide effective processing with a minimized amount of processing solution in each tank are unsusceptible to daily variations in processing quantity because a larger proportion of the processing solution in each tank is replaced by replenisher solution, but are affected by the degree of exhaustion of processing solution (that is, the amount of silver in film to be developed) varying between different types of film. Therefore, the slit type processing tanks can introduce a difference in processing performance between different types of film.